If (A(t)=40+6t) and (B(t)=76+3t), at what (t) will (A(t)) be (9) more than (B(t))?
Answer and explanation
Correct answer: \(t=15\)
The condition is \(A(t)=B(t)+9\). So, \(40+6t=76+3t+9\), which gives \(3t=45\) and hence \(t=15\). Checking: \(A(15)=130\) and \(B(15)=121\), so the difference is \(9\). At \(t=14\), the difference is only \(6\), so it is not correct. Exam tip: translate “9 more than” as \(A=B+9\).
Frequently asked questions
What is the correct answer to this question?
\(t=15\)
Why is this the correct answer?
The condition is \(A(t)=B(t)+9\). So, \(40+6t=76+3t+9\), which gives \(3t=45\) and hence \(t=15\). Checking: \(A(15)=130\) and \(B(15)=121\), so the difference is \(9\). At \(t=14\), the difference is only \(6\), so it is not correct. Exam tip: translate “9 more than” as \(A=B+9\).
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Introduction to Polynomials. Topic: Linear growth and decay.
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